<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style type="text/css">
			#f1 div{
				height: 100px;
				width: 100px;
				margin: 3px;
				border: 4px solid greenyellow;
				float: left;
			}
			#f1 div:nth-of-type(2n+1){
				float: right;
			} 
		</style>
	</head>
	<body>
		<div id="f1">
			<div id="d1">1</div>
			<div>2</div>
			<div>3</div>
			<div>4</div>
			<div>5</div>
			<div>6</div>
			<div>7</div>
			<div>8</div>
		</div>
	</body>
</html>
